A number of Zynga (Nasdaq:ZNGA) insiders — company executives and venture capital backers — are taking heat today for cashing out some of their holdings in the company in April. The liquidation came just prior to a slowdown in the company's growth and stock price plunge (shares down to around $3 this week, from the IPO price of $10).

However, venture backer Avalon Ventures of Cambridge wasn't among those selling shares. SEC filings show that Avalon did not participate in the April sale of shares at $12 a piece, as did VCs such as Union Square Ventures and Institutional Venture Partners.

In fact, Zynga's recent proxy filing shows Avalon still holding the 34.68 million shares it had at the time of Zynga's IPO in December.

Those shares are now worth about $108 million — compared to the roughly $416 million they were worth when insiders sold shares in April. A sale of, say, 5 million shares (the amount sold by Union Square) would have netted $60 million for Avalon.

But, of course, it would also have meant a share in the swirling negative publicity now that Zynga is under scrutiny.

Worth noting: Avalon, whose general partner Rich Levandov led the firm's Zynga investment in 2008, has already made a healthy return on the deal. Avalon invested $4.5 million into Zynga, and in 2011 sold shares worth $20.9 million.

And so even with shares worth $108 million — or less if shares continue to drop — the opportunity is there to sell shares and augment an already-good return at any time.

It just won't be the mega-blockbuster return investors once hoped for.